1. Field of the Invention
The present invention relates to a valve with a level gauge for a liquefied carbon dioxide container.
2. Related art statement
A container for containing liquefied carbon dioxide is a cylindrical high pressure container. Such containers are usually much more slender than the wide containers used for liquefied petroleum gas which are generally used in the home and so on, as seen in the market.
Slender containers such as liquefied carbon dioxide containers are different from liquefied petroleum gas containers in the fact that they are often handled very roughly in the transportation. For example, they are roughly tilted or laid down and rolled over and over.
Therefore, the valve with a level gauge assembled in such container is especially desired to endure such rough handling, to be free from the damages and to keep its accurate performance.
The usual valve of this kind adopted to a liquefied petroleum gas container comprises, as disclosed in U.S. Pat. No. 2,634,608, and shown in FIG. 18 in the present application, a body being adapted to be screwed in a threaded hole formed at an upper end of the cylindrical container 101, and a level gauge combined with the body. Such level gauge comprises an indicating member inserted in said body and adapted to move up and down, a rod 113 having upper and lower parts, said upper part is inserted in said body and is adapted to slide up and down, and said lower part is extruded into said container 101, a detecting member fixed to the upper end of said rod 113 so as to move said indicating member by magnetic attraction therebetween, and a vertically elongated rigid float 115, inserted in said container 101 adapted to move up and down freely, and connected rigidly to the lower end of said rod 113 at the upper end thereof.
When said container 101 is tilted or laid down, as said float 115 is hung at its one end by said rod 113, the weight of said float 115 is fully supported by said rod 113. Said rod 113 is made so slender that said rod 113 is very easily and permanently bent by the weight of said float 115, and that the accurate performance of the level gauge is easily lost thereafter.
In order to prevent such bending of the rod 113, an improved valve disclosed in U.S. Pat. No. 2,634,608, and shown in FIG. 18 in the present application, comprises a cylndrical casing 160 additionally.
The inner periphery of said casing 160 limits the range where said float 115 is movable and the deflection of said rod 113 does not exceed the range of elastic deflection. Thus, said rod 113 is prevented from its permanent deformation.
However, the liquid level gauge of this kind implies following problems when it is adopted to such container containing liquefied carbon dioxide:
(a) It is necessary to protect said rod 113 and said cylindrical float 115 by said tubular casing 160 surrounding them in order to prevent the rod 113 from permanent bending caused by the weight of the float 115 acting thereon when the container is tilted or laid down. However, as said casing 160 is also hung at one end by said body, it may be deflected by the weight of itself, too. And it is necessary to restrained the deflection of said casing within the range where the deflection of the rod 115 does not exceed the range of elastic deflection. To this end, the radial sizes of said casing 160, and consequently these of said level gauge, are made large. As the result this usual valve is not suitable for slender containers such as liquefied carbon dioxide containers.
(b) Moreover, as the casing 160 is made axially long to cover around the long float 115, it is necessary to provide such slider 161 consisted with balls or projections between the peripheries of the float 115 and the casing 160 in order to make the sliding motion of the rod 113 and the float 115 smoother in the casing 160 with decreased resistance. Therefore, the level gauge is made complex and expensive.
(c) Further more, even if the rod 113 and the float 115 were housed in the casing 160 for protection of them, in the case of the slender container such as that for containing liquefied carbon dioxide, that may be roughly tilted or laid down and rolled over and over in transportation, it is possible that the casing 160 itself is deflected and collides with the inner periphery of said container 101, and is broken by the collision with the wall of container.
As the result, the usual level gauge disclosed above is unsuitable for liquefied carbon dioxide containers which are handled very roughly.